Nitration products of monoazo dyestuffs



formula:

m treated with nitrating me h b nz ns methoxy-l :l"- azobenzene, 2-nitro-4 -amino-1: 1'-

Patented Oct. 30, 1945 Nrra TmN PRODUCTS F MONOAZO 1 Y nYEs'rnFFs Friedrich Felix, Basel, Switzerland, and Werner .Ziircher, deceased, late ofBasel, Switzerland,

byJosef Ziircher, administrator, Horgen, Switzerland, assignors to Society of ChemicalIndustry in Basle, Basel, Switzerland, a Swiss No Drawing. Application August 2, 1943, Serial N0.' 197,094.I1i1 Switzerland January 5,1939

This application is a continuation in part of our application Serial No. 312,618, filed January 1940.

It has been found thatnew "a'z'o, dyestufis are obtained when monoazo dyestuifs of the general in which R1 andRa'represent aromatic nuclei of the benzene series, and :c and 1/ represent membersof the group consisting of; hydrogen and alkyl a d substituted alkyl radicals, and in which 7 Claims. (Cl.260l+2.0.5) a H are, for example 4-nitror2-chloro-4-amino-l:-1-

azoloenzene, .4-nitro-2-chloro- 4 diniethylaminofl l if -azoben'zene, 2:5-dichloro-4C-amino-1 1 -azobenzene, 2:5 dichloro-4-dimethylamino 1:1-

4; azobenzene, 4-nitro-2 6-dichloro-4 -amino-1 1- azobenzene, 4 nitro 2:6-dichloro-4-dimethylamino-l: 1'-az0benzene, 3-nitro-5-chloro-4'-amino lzlazobenzene, '2:4-dinitro-4'-amino-1:1- azobenzene, 2: 4-dinitro-6-chloro-4-amino-1 1- "i azobenzene.

moreover, the radical R1 carries atleast onenitro I group, and in which the atomic grouping N N-- stands in the paraposition to the atomic groupin i agents. Of particular interest are those dyestufis are obtained when azo dyestufis oi theformula:

No; i l

are treated with nitrating agents. Particularly good dyeing behaviour is manifested by those dyestufis'which areob'tained by nitrating those nitroaminobenzenes in which the nitro group stands in the 4- or! 3-position in relation to the azo group. i 1 a a process is thusconcerned with the treatment of aminoazoj dyes'tufis with nitrating agents. Among the dyestuffs suited 'forlthe process may be mentioned products such as 4-nitro-4'-amino- 1: 1'-azobenzene, 4-nitro-4'-dialkylamino-1 1- azobenzenes, such as, for example, 4-nitro-4'- dimethylamino-l 1 -azobenzene, 4-nitro-4'-diethylamino-l l-azobenzene, 4-nitro-4' -methylethylamino-l 1'-azobenzene, 4-nitro-4'-m'ethy1- butylamino-l:l -azobenzene; further, 4-nitro-4'- amino- 5'emethyle-l'zl'-azobenzene, 4- nitro-4'- amino-5f methoxy-l': 1'-azobenzene, 3-nitro-4famino 1: 1'-azobenzene, 3 nitro-4-amino -5"- azobenzeneQ 2 -nitro 4 '-amino-5'-'methyl-1:1'; azobenzene, 4 nitro-4'-amino-6'-chloro-1 :1"-azo benzene, etc.

whichj'alsonome under consideration These dyestufis may be treated with nitrating agents according to the customarymethods, for example, by means of concentrated or dilute nitric acid, particularly in the presence of sulphuric acid or othersolvenvas, ior example, glacial acetic acid, acetic acid anhydride, chlorosulphonic acid, halogenated hydrocarbons or dioxane. Dyestuffs which contain primary or secondary amino groups may be nitrated as such, for example, in concentrated sulphuric acid; on the other hand, they which may be previously acidylated in the amino'group by treatment with acidylating agents, for exam ple, by treating with acetic acid anhydride, and then subsequently subjected to the nitration.

Similarproducts may also be obtained if these dyestufis containing free amino groups are acidylated only after nitration. These dyestufis are insoluble in ,water. They may find particular use in the dyeing of acetate rayon. The newdyestufis form yellow to red powders and dye acetate rayonin shades of greenish yellow, yellow, orange and brown. 7

The new dyestuffs do not represent homogeneous products but are mixtures. However, it has been ascertained that these mixtures consist chiefly of azo-dyestufis of the formula:

It R N=NRaN wherein Ri and stand for nuclei of the benzene series and a: and y stand for a member o-fthe group consisting of hydrogen and alkyl radicals: wherein furthermore the radical R1 contains at least onenitro' group andthe'radical R2 contains a nitro group, and wherein the atomic groupings --N=N'-, and

stand in paraposition to one another. By the aforesaid property that the dyestuils oi the present-invention are pronounced acetate -rayon dye- Applicants have, however, ascertained that this is an obvious error, and that'it is -apparentlya question here of the compound of the formula:

in water, but which dyes acetate rayon in completely fast-to-light shades of reddish-yellow after it has been brought into a fine state of dispersion ,bytreatment with Turkey-red oil or other soap-like dispersing agentyor with sulphite cellulose waste liquor. The new product represents a mixture of different products, the

(however in very impure state). tion of the product hasmoreover already been previously: confirmed" by fMeldola in said fBerichteP v61. 19'Qf18'86, pages 3243-3244.

, Particularly valuable areithe mix'ture'swhich' consist "mainly of the dyestufis of the general formulaic H.

wherein one :0 stands for a'nitro group and the other :1: stands for hydrogen.

The process 'permit's among other things the manufacture of a series of amino azo dyestuffs of a new 'typefwhi chmay be usedto "dye acetate rayon, particularly j for the dyeing of yellow shades. Over the amino azo dyestuffs dyeing in similar shades, the products possess the advantage of being nonl phototropic"and'possessing good'iastness to light at; thesametima'which is a property of particularly great interest where the 'preparationofgrey and green combination shades is concerned. j "Dyestuffs of .th'is'typewhich'contain aifr'ee amino group may be treated either'in substance, on the fibre, or on another substrate, whereby dyestuffs or dyeings possessing otherproperties maybeobtained. H The following examples -il1ustrate-"the' inverttion, the partsyunless'otherwise stated,being by weight; Example 1 V 300 parts of sulphuric acid are cOOledtoO C, and 25 parts of {l-nitro-l'--a:mino-1 l' -azobenzene oi the formula:

are added with stirring. The dyestuff dissolves in the sulphuric acid, probably with the formation of its sulphate, 'giving a yellow colour." A mixture containing 7 parts of concentrated sulphuric acid and 7 parts 'of concentrated nitric acid is now added, car'e being taken that the temperature is not allowed to"rise"ab ove'0 C. The solution new changes to an orange-red colour. After stirring has been continued for half-an hour, the solution is poured into ice water, and the dyestuff which separates is filtered off. By washing with water, if desired, by stirring with Water and addition of an alkali, such as ammonia, the dyestuff' suspension. is exactly neutralized. In the dry state, the new dyestuff is a yellow brown-to brown-red powder whichis insoluble This constitu- .main constituent which determines the properties of the new dyestufi being a product of the formula:

I NOGNfli-Q-Mh r 7 02 It dissolves in acetic acid ethylester to a yellow solution.

In a similarmanner there is also treated the dyestuff ofthe formula:

obtained by diazotizing 4-nitro-l-aminobenzene and coupling with N- methylaminobenzene; ,3 l Eram ple 2 V q j.

6.4 parts of 2.-nitro-4'-amino-4-methyl-1:l-

azobenzene of the formula: I

are dissolved in 75 parts by volume of concentrated sulphuric'acid. 3.5 parts of'a solution'of 1.75 parts of nitric acid in 1.75 parts of sulphuric acid are dropped into this solution-at a-temperaof 0-5 0., and the temperature is then allowed to rise slowly to about 10 C. When the nitration is completed, the reaction mixture is poured into ice water, and the precipitated dyestuif is filtered off. It is then preferably stirred up with water and neutralized by addition of alkali. In the dry state the new... dyestufi is a dark powder which, when'converted into'a high "stateofdispersion, is suitable for a the. dyeing of acetate rayon in brownish-yellow shades.

A similar procedure, is followed when nitrating 2-nitro-4'-dimethylamino-1:l-azobenzene of the formula:

" Em a,

parts by Volume of concentrated sulphuric acidare cooledto 0 C.,and-1&8'partsjof l-nitro- Z-chloro-AH-amino-l:l-azob enzene 10f the formula:

l l I, l 9 s i whereby a dyestufif which possesses im pr pertiesisobtamed, p Example! 12.1 parts of 3-nitro -4'-amin" otiiirga ebnzene N: are dissolved at 0 C. in 150 parts by volume of sulphuric acid. Then, at about 10 C., a mixture consisting of 3.3 parts of nitric acid and 3.5 parts of sulphuric acid is added. Stirring is continued for some time at 10-20 C., and the solution is then poured into ice water, when the new dyestufl! is precipitated. It is filtered off, washed and, if desired, freed from acid by neutralizing. In the dry state, it is a dark yellow to brown powder which is insoluble in water, but which dyes acetate rayon from a fine aqueous suspension in fast yellow shades by known methods.

,The new product consists mainly of a product of the general formula:

NO: I N0:

which determine also its property as an acetate rayon dyestufl.

A dyestufl possessing similar properties is obtained by the following procedure. 3-nitro-4'- amino-l:1'-azobenzene is acetylated by means of acetic acid anhydride. 15 parts of this acetyl compound are dissolved in 100 parts of glacial acetic acid at 50-60 C., and a solution consisting of 3.5 parts of nitric acid in about the same quantity of glacial acetic acid is added. The dyestufl. may be isolatedby removal of the glacial acetic acid by distillation, preferably under reduced pressure, and it may now be treated with saponifying agents in order to split off the acetyl radical.

Example 5 13.5 parts of 4 -nitro-4'-dimethylamino-1:lazobenzene of the formula:

dissolved in 150 parts by volume of concentrated sulphuric acid at about C., are treated with a solution consisting of 3.5 parts of nitric acid dissolved in about the same quantity of concentrated sulphuric acid. The reaction solution is poured into ice water, and the dyestufi. is isolated by filtration and neutralization. In the dry state, it forms a dark brown powder, which dyes acetate rayon in brown tones.

This dyestuff may also' be nitrated by treatment with nitrosyl chloride in an organic solvent, for example, in tetrachloroethane.

The nitration product prepared in this manner from 3-nitro-4-dimethylamino-l:1' azobenzene also dyes acetate rayon in brown tones.

What we claim is:

1. Process for the manufacture of azo-dyestufis, comprising treating with nitrating agents monoamino-monoazo-dyestufls, which are free from sulpho groups, of the general formula wherein R1 and R2 stand for nuclei of the benzene series; and wand 11 for a member of the group consisting of H andalkyl radicals, wherein furthermore the radical R1 contains at least once a nitro group, and wherein the atomic groupings --N=N and stand in para position to one another.

2. Process for the manufacture of azo-dyestuffs, comprising treating with nitrating agents mono-amino-monoazo-dyestufis, which are free from sulpho groups, of the general formula wherein R1 and R2 stand for nuclei of the benzene series, wherein furthermore the radical R1 contains at least once a nitro group, and wherein the atomic groupings --N=N- and NH2 stand in para position to one another.

3. Process for the manufacture of azo-dyestuffs, comprising treatingwith nitrating' agents the monoazo-dyestuff of the formula NOON: ONE:

4. Process for the manufacture of azo-dyestuffs, comprising treating with nitrating' agents the monoazo-dyestufi of the formula 5. A composition of matter consisting of the nitration products of the dyestuffs of the general formula in which on :1: stands for a nitro group and the other :1: stands for a hydrogen atom, which nitration products are mixtures containing mainly products of the general formula:

which is a mixture containing mainly a product of the formula:

and, when dry, is a yellow to brown powder insoluble in water but dissolving in acetic acid ethylester to a yellow solution and dyeing acetate rayon from a fine aqueous suspension intensive yellow shades.

'I. A composition of matter consisting of the nitration product of the dyestufi of the formula;

which is a mixture containing mainly a, productof the formula:

YNO:

and; when dry, is a ye11ow,to brown powder 111-; soluble in water but dissolving: in acetimaoid ethylester to a yellowgsolution and dyeing acetate rayon from a..fine aqneoussuspension int'ensiii'yeilowshade's. FRIEDRICH" FELIX. 5 7 JO S EF ZfiRCI-IER. Administrator oT-rthe Estate of Werner Zitrcher,

Deceased. 

